It's a great thing to have the user input a special kind of data. It's often used in software, but
rarely on the internet because web browsers don't come with such a control.

If a browser does not support it or has javascript turned off, it can be hacked so they can still
enter some data (but not as nicely).

Requirements:

Mac: Safari and Camino work fine.
Internet Explorer (5.2.3) works but does not submit the value along with a form. If you
need that feature, make a (hidden) form field and attach an onchange event to the slider,
just like in example 1.
It's a problem from Explorer, not from the javascript code, and the development of Internet Explorer on Mac
has been abandoned.

DocType

Not all doctypes work. This one does:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
For example don't use "XHTML 1.0".
If this is a problem with your current setup, you can stick the slider into an iframe.